In a known drawing apparatus of this type (German published application, DE-OS Pat. No. 28 21 612), movement of a tubular writing pen between its various positions is effected by means of a linkage, comprising three different levers. One lever, at one end, engages the tubular writing pen and the other lever, at one end, engages the slide having the sealing element. The levers pivotably are supported and coupled with one another in such a manner that when the lever engaging the slide is moved by a drive mechanism, the various shifts in position are effected. For instance, the tubular writing pen is raised out of its rest position into an intermediate position, then the slide is shifted laterally and thus moves the sealing element out of range of the writing tip, and finally the tubular writing pen is lowered into its working position.
This known apparatus functions very reliably and satisfactorily in practice, but it has the disadvantage of having a relatively large number of individual parts, so that its manufacture and servicing become quite expensive.